There are <fewer/less> people ...

Hi everybody,
The use of 'fewer' is giving me tough time.
1. There are -fewer- people here than there were yesterday.
2. He had -fewer- men than in the previous campaign.
Some of my friends say, "I should use 'less' in the place of 'fewer'.
Please guide me with your comment.
Thanks,
Er.S.M.M.Hanifa

I try to be as understanding as I can about language, but the fewer/less issue remains one of my pet peeves (pet hates for my British friends). As SwissPete notes, you need fewer or newer friends... or something like that.